“wlx123 Interface doesn’t support scanning : Device or resource busy”

this error occurs during manual terminal bash based scanning of wifi wlan networks:

hostnamectl; # tested on
Operating System: Debian GNU/Linux 12 (bookworm)  
          Kernel: Linux 6.1.0-13-686-pae
    Architecture: x86
su - root
apt update
# get iwlist tool
apt install wireless-tools
# check what interfaces are wifi enabled
ip -c a
# like this (also gives nice overview of all available networks per interface)
nmcli dev wifi
# start a manual scan with wlx123 as interfacename
iwlist wlx123 scan

it means that another process (NetworkManager.service) is already using this wifi interface to scan and no other process can start a scan.

to fix this, temporarily stop NetworkManager.service

systemctl stop NetworkManager.service

# this is a nice one-liner that allows
# to monitor the signal strength of a certain wifi network
while true; do ifconfig wlx123 up; iwlist wlx123 scan|grep -B 3 -A 3 SSID-OF-WIFI-IN-QUESTION; sleep 5; clear; done;

then to improve signal:

  • move position of notebook
  • or move antennas in different directions and see if signal strength gets better or worse
  • if the signal is not strong enough: get a bigger antenna 😀

this “double yagi” WIFI antenna was tested with a TP-LINK router and works pretty okay 😀 (c.a. +30% signal gain)

creditz go to https://hpl.hp.com/personal/Jean_Tourrilhes/Linux/Tools.html

The Wireless Tools (WT) is a set of tools allowing to manipulate the Wireless Extensions. They use a textual interface and are rather crude, but aim to support the full Wireless Extension. There are many other tools you can use with Wireless Extensions, however Wireless Tools is the reference implementation.

  • iwconfig manipulate the basic wireless parameters
  • iwlist allow to initiate scanning and list frequencies, bit-rates, encryption keys…
  • iwspy allow to get per node link quality
  • iwpriv allow to manipulate the Wireless Extensions specific to a driver (private)
  • ifrename allow to name interfaces based on various static criteria

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